The invention relates to distribution valves, particularly to distribution valves for distributing water from the high-pressure side of a swimming pool pump to various groups of cleaning heads located along the inner surface of a swimming pool, particularly to such distribution valves which require less torque to be produced by an internal impeller and gear reduction assembly, and more particularly to such distribution valves which can deliver a large amount of water for each outlet port with a low water pressure drop across an open the outlet port with a valve.
A number of multi-port distribution valves for sequentially distributing pressure from the high pressure port of a swimming pool pump to various groups of cleaning heads imbedded in the bottom and side walls of the pool are known. These include the distribution valve disclosed in commonly assigned U.S. Pat. No. 4,523,606 by Gould et al., issued Jun. 18, 1985, entitled "DISTRIBUTION VALVE" and U.S. Pat. No. 4,570,663 by Gould et al., issued Feb. 18, 1986, entitled "DISTRIBUTION VALVE WITH DUAL CAMS TO PREVENT UNCONTROLLED EXCURSIONS OF VALVE BALLS", both of which are incorporated herein by reference. Each of the distribution valves disclosed in the above referenced patents includes an impeller-driven gear reduction mechanism and a plurality of outlet valves controlled in response to the gear reduction mechanism. U.S. Pat. No. 4,523,606 and 4,570,663 disclose gear reduction mechanisms which include a stationary planetary gear disposed about a vertical axis of the distribution valve, a pair of symmetric gear assemblies each driven by a gear attached to the impeller, with each of the symmetric gear assemblies being supported on a rotary gear support base, and each also having an outer gear engaging the teeth of the planetary gear to cause the rotary gear assembly base to rotate in response to rotation of the impeller and thereby drive at least one foot-shaped cam which rotates through a 360.degree. angle and sequentially displaces balls from a valve seat of an outlet port. In each of the above prior distribution valves the pool return water from the high pressure side of the pool pump is fed into a vertical inlet pipe connected to the top of a dome-shaped cover section of the distribution valve.
The above mentioned distribution valves have been widely used, and the gear and impeller mechanisms have proven highly reliable.
However, a fairly large force is required to be applied by the gear reduction mechanism to turn the cam that pushes the valve balls away from their valve seats in order to open the valves. Common mineral deposits may occur on the valve balls and gears and may further increase the amount of torque required to be applied by the cam a to push the valve balls from their valve seats. The increased amount of required torque greatly increases the amount of stress on the gears of the planetary gear assembly. The results of the stress include "locking up" of the gear reduction mechanism and breaking of the gears in the planetary gear assembly, resulting in the need for repair and maintenance and associated downtime for the pool recirculation and cleaning system. That causes increased warranty replacement costs and loss of customer good will.
The above described distribution valves typically require approximately 18-22 in. lbs. of torque to be applied by the planetary gear assembly to rotate cam as necessary to displace the various valve balls in order to open the valves. It would it would be desirable to provide a distribution valve which requires substantially less torque to be produced by the gear reduction mechanism of the distribution valve in order to ten the cam, which then pushes the valve balls away from their respective valve seats in order to open the valves, because this would reduce stress and wear on the gears of the planetary gear assembly, and would result in longer product life before repairs are needed.
It would be desirable to increase the amount of water that can be pumped through each port of the above mentioned distribution valves without increasing the water pressure drop across the open valve. It would be especially desirable to accomplish this benefit without an expensive re-tooling of the molds needed to manufacture the upper and lower housings of the above described distribution valves. It also would be very desirable to accomplish the same benefit without having to redesign the planetary gear assembly presently being used. It also would be very desirable to be able to retrofit existing distribution valves with an improved valve structure which does not have the above mentioned problems associated with mineral deposits and which can be accomplished at a very low cost, perhaps even by do-it-yourselfers.